--- description: Configure custom DHCP options on the Cloudflare One Appliance DHCP server, including options for PXE, PXELINUX, and iPXE boot. title: DHCP server options image: https://developers.cloudflare.com/cloudflare-wan/configuration/appliance/network-options/dhcp/dhcp-options/og.png?v=66232a6a7fca92e8 --- [Skip to content](#main-content) > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/cloudflare-wan/llms.txt > Use this file to discover all available pages before exploring further. # DHCP server options Last updated Sep 2, 2026|Copy as Markdown| [View as Markdown](https://developers.cloudflare.com/cloudflare-wan/configuration/appliance/network-options/dhcp/dhcp-options/index.md)| [Agent setup](https://developers.cloudflare.com/agent-setup/) When the Cloudflare One Appliance is configured as the DHCP server for a LAN, you can attach **custom DHCP options** to the leases it issues. This is commonly used for: - **Network boot** of workstations or kiosks with PXE, PXELINUX, or iPXE (options 43, 60, 66, 67, 175, 209, and 210). - **VoIP phone provisioning** (option 66 — TFTP server). - **Vendor-specific client configuration** (option 43 with vendor sub-options). DHCP options can only be configured when the appliance is acting as the DHCP server. They have no effect when the appliance is in [DHCP relay](https://developers.cloudflare.com/cloudflare-wan/configuration/appliance/network-options/dhcp/dhcp-relay/) mode. ## Configure DHCP options 1. Go to the **Connectors** page. [Go to **Connectors** ↗](https://dash.cloudflare.com/?to=/:account/magic-networks/connections) 2. Go to the **Appliances** tab > **Profiles**. 3. Select your Cloudflare One Appliance > **Edit**. 4. Select **Network Configuration**. 5. In **LAN configuration**, select **Add LAN** to create a new LAN, or select an existing LAN > **Edit**. 6. Make sure **This is a DHCP server** is selected. 7. In **DHCP server options**, select **Add DHCP option**. 8. Choose one of the listed common options, or select **Add custom option** to enter your own option code, type, and value. 9. Select **Save**. Note You will need your [account ID](https://developers.cloudflare.com/fundamentals/account/find-account-and-zone-ids/) and [API token](https://developers.cloudflare.com/fundamentals/api/get-started/account-owned-tokens/) to use the API. You can also configure DHCP options via the API and Terraform using the `dhcp_options` field on the LAN's `dhcp_server` configuration. Create a [`PUT` request](https://developers.cloudflare.com/api/resources/magic_transit/subresources/sites/subresources/lans/methods/update/) to update the LAN where you want to configure DHCP options:
Required API token permissions At least one of the following token permissions is required: - Magic WAN Write - Magic Transit Write
*Update Site LANbash* ```bash curl "https://api.cloudflare.com/client/v4/accounts/$ACCOUNT_ID/magic/sites/$SITE_ID/lans/$LAN_ID" \ --request PUT \ --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \ --json '{ "lan": { "static_addressing": { "dhcp_server": { "dhcp_options": [ { "code": 67, "type": "text", "value": "boot/x64/pxelinux.0" } ] } } } }' ``` ## Option format Each option is defined by three fields: | Field | Description | Example | | --- | --- | --- | | `code` | The DHCP option code (1–254). | `67` | | `type` | The value encoding: `text`, `hex`, `ip`, `byte`, `short`, `integer`. | `text` | | `value` | The option value, encoded per `type`. | `boot/x64/pxelinux.0` | ### Value type encoding | Type | Format | Example value | | --- | --- | --- | | `text` | A UTF-8 string (max 255 bytes). | `boot/x64/pxelinux.0` | | `hex` | A colon-separated sequence of hex bytes, used for sub-options (max 255 bytes). | `01:04:aa:bb:cc` | | `ip` | A dotted-quad IPv4 address. | `10.20.30.40` | | `byte` | An unsigned 8-bit integer (0–255). | `1` | | `short` | An unsigned 16-bit integer (0–65535). | `512` | | `integer` | An unsigned 32-bit integer (0–4294967295). | `0` | ### Restricted option codes - Options `0` and `255` are reserved by [RFC 2132 ↗︎](https://www.rfc-editor.org/rfc/rfc2132) and cannot be configured. - Options `3`, `6`, and `51` are managed by the Cloudflare One Appliance and cannot be configured, since they conflict with connector-managed configuration (default gateway, DNS servers, and lease time). - Each option code can only be used once per LAN. Duplicate option codes are rejected. ## Common network boot options The most frequently used network boot options are: | Option | Type | Purpose | | --- | --- | --- | | 43 | `hex` | Vendor-specific information. The vendor defines the sub-option layout. | | 60 | `text` | Vendor class identifier, typically `PXEClient`. | | 66 | `text` | TFTP server name. | | 67 | `text` | Boot file name, for example `ipxe.pxe` or `undionly.kpxe`. iPXE also accepts a URI, such as an HTTP URL for an iPXE script. | | 175 | `hex` | Client-specific encapsulated options used by Etherboot and iPXE. IANA lists this option as tentatively assigned and does not define its payload. | | 209 | `text` | PXELINUX configuration filename or path, loaded through TFTP. | | 210 | `text` | PXELINUX TFTP path prefix, prepended to option 209. | For a complete list of standard DHCP option codes, refer to the [IANA BOOTP/DHCP parameters registry ↗︎](https://www.iana.org/assignments/bootp-dhcp-parameters/bootp-dhcp-parameters.xhtml). ## Validation and apply behavior Before applying a new DHCP options configuration, the appliance: 1. Stages the change to a temporary configuration file. 2. Validates the syntax with the underlying DHCP server. 3. **On success**, atomically swaps the staged configuration into place and reloads the DHCP server with no service interruption. 4. **On failure**, discards the change and returns the underlying validation error to the caller — shown as a field error in the dashboard, or in the API response for API and Terraform callers. The live DHCP service is never restarted with an unverified configuration. This means a malformed option will be rejected at apply-time rather than disrupting DHCP service for clients on the LAN. Was this helpful? 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